This clinical study distinguishes itself by being the first to evaluate the vascular changes induced by esterified estrogens 0.625 mg/day alone and with the addition of methyltestosterone or medroxyprogesterone acetate, as opposed to conventional-dose conjugated estrogens 0.625 mg/day or equivalent. This study will specifically evaluate changes in nitric oxide physiology induced by estrogen replacement therapy (ERT) and combination therapy (esterogen-progesterone and estrogen-androgen) at conventional doses, as opposed to acute, high-dose regimens, which are likely to be less representative of the clinical setting. We are actively recruiting and screening candidates. Nine candidates were screened and consented; five were excluded and four have initiated hormonal therapy and began the dynamic studies. Response to multiple recruitment efforts has been good but many did not meet the inclusion criteria or felt the study was either too invasive or wanted to choose their study group (estrogen or placebo). Study enrollment will increase once all avenues of recruitment within Mayo and the communities are in place.